fix: Show parent directory in file mention chips

[charlesvien]

Problem

File mention chips only show the filename, making it hard to distinguish between files with the same name in different directories. Absolute file paths pasted into @ mentions aren't recognized at all.

Changes

1. Show parent directory prefix in file mention chip labels (e.g. components/Button.tsx)
2. Add tooltip on file chips showing the full path
3. Recognize and chipify absolute file paths in @ mention suggestions
4. Add fileExists tRPC endpoint to validate absolute paths before suggesting them

How did you test this?

Manually

[charlesvien]

• fix: Show parent directory in file mention chips #1472 👈 (View in Graphite)
• fix: Fix Enter key blocked after dismissing empty suggestion popup #1471
• fix: Open active file in external app instead of repo directory #1470
• fix: Rename bypass permissions to auto-accept permissions #1469
• fix: Polish message editor, settings dialog and minor UX tweaks #1468
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[charlesvien]

Merge activity

• Apr 3, 1:05 AM UTC: A user started a stack merge that includes this pull request via Graphite.
• Apr 3, 1:26 AM UTC: Graphite rebased this pull request as part of a merge.
• Apr 3, 1:32 AM UTC: @charlesvien merged this pull request with Graphite.